The Experts below are selected from a list of 1185 Experts worldwide ranked by ideXlab platform
Francois Ollivier - One of the best experts on this subject based on the ideXlab platform.
-
modal proportional and derivative state active control applied to a simplified string instrument
Journal of Vibration and Control, 2016Co-Authors: Simon Benacchio, Baptiste Chomette, Adrien Mamoumani, Francois OllivierAbstract:This study proposes an application of modal active control to musical string instruments. Its aim is to control the modal parameters of the Soundboard in order to modify the sound of the instrument. Using both state and derivative state modal control, a method is given, from the modeling of the active structure through to the design of the control system. Issues such as the identification of the structure’s characteristics or the stability of the control system are dealt with for this original control method. Then, this technique is applied to a model of a simplified string instrument Soundboard. Time simulations are conducted to study its effect on the instrument vibration. They show that, thanks to Soundboard modal active control, it is possible to modify the amplitude of the sound harmonics to change the timbre as well as the sound level of the instrument.
-
Modal PD state active control applied to a simplified string instrument
Journal of Vibration and Control, 2015Co-Authors: Simon Benacchio, Baptiste Chomette, Adrien Mamou-mani, Francois OllivierAbstract:This study proposes an application of modal active control on musical string instruments. Its aim is to control the modal parameters of the Soundboard in order to modify the sound of the instrument. Using both state and derivative state modal control, a method is given, from the modeling of the active structure through to the design of the control system. Issues such as the identification of the structure's characteristics or the stability of the control system are dealt with for this original control method. Then, this technique is applied on a model of a simplified string instrument Soundboard. Time simulations are conducted to study its effect on the instrument vibration. They show that, thanks to Soundboard modal active control, it is possible to modify the amplitude of the sound harmonics to change the timbre as well as the sound level of the instrument.
Simon Benacchio - One of the best experts on this subject based on the ideXlab platform.
-
modal proportional and derivative state active control applied to a simplified string instrument
Journal of Vibration and Control, 2016Co-Authors: Simon Benacchio, Baptiste Chomette, Adrien Mamoumani, Francois OllivierAbstract:This study proposes an application of modal active control to musical string instruments. Its aim is to control the modal parameters of the Soundboard in order to modify the sound of the instrument. Using both state and derivative state modal control, a method is given, from the modeling of the active structure through to the design of the control system. Issues such as the identification of the structure’s characteristics or the stability of the control system are dealt with for this original control method. Then, this technique is applied to a model of a simplified string instrument Soundboard. Time simulations are conducted to study its effect on the instrument vibration. They show that, thanks to Soundboard modal active control, it is possible to modify the amplitude of the sound harmonics to change the timbre as well as the sound level of the instrument.
-
Mode tuning of a simplified string instrument using time-dimensionless state-derivative control
Journal of Sound and Vibration, 2015Co-Authors: Simon Benacchio, Baptiste Chomette, Adrien Mamou-mani, Victor FinelAbstract:In recent years, there has been a growing interest in smart structures, particularly in the field of musical acoustics. Control methods, initially developed to reduce vibration and damage, can be a good way to shift modal parameters of a structure in order to modify its dynamic response. This study focuses on smart musical instruments and aims to modify their radiated sound. This is achieved by controlling the modal parameters of the Soundboard of a simplified string instrument. A method combining a pole placement algorithm and a time-dimensionless state-derivative control is used and quickly compared to a usual state control method. Then the effect of the mode tuning on the coupling between the string and the Soundboard is experimentally studied. Controlling two vibration modes of the Soundboard, its acoustic response and the damping of the third partial of the sound are modified. Finally these effects are listened in the radiated sound.
-
Modal PD state active control applied to a simplified string instrument
Journal of Vibration and Control, 2015Co-Authors: Simon Benacchio, Baptiste Chomette, Adrien Mamou-mani, Francois OllivierAbstract:This study proposes an application of modal active control on musical string instruments. Its aim is to control the modal parameters of the Soundboard in order to modify the sound of the instrument. Using both state and derivative state modal control, a method is given, from the modeling of the active structure through to the design of the control system. Issues such as the identification of the structure's characteristics or the stability of the control system are dealt with for this original control method. Then, this technique is applied on a model of a simplified string instrument Soundboard. Time simulations are conducted to study its effect on the instrument vibration. They show that, thanks to Soundboard modal active control, it is possible to modify the amplitude of the sound harmonics to change the timbre as well as the sound level of the instrument.
Antoine Chaigne - One of the best experts on this subject based on the ideXlab platform.
-
Operational transfer path analysis of a piano
Applied Acoustics, 2018Co-Authors: Jin Jack Tan, Antoine Chaigne, Antonio AcriAbstract:Abstract The piano sound is made audible by the vibration of its Soundboard. A pianist pushes the key to release a hammer that strikes the strings, which transfer the energy to the Soundboard, set it into vibration and the piano sound is heard due to the compression of air surrounding the Soundboard. However, as piano is being played, other components such as the rims, cast-iron frame and the lid are also vibrating. This raises a question of how much of their vibrations are contributing to the sound as compared to the Soundboard. To answer this question, operational transfer path analysis, a noise source identification technique used widely in automotive acoustics, is carried out on a Bosendorfer 280VC-9 grand piano. The “noise” in a piano system would be the piano sound while the “sources” are Soundboard and the aforementioned components. For this particular piano, it is found out that the Soundboard is the dominant contributor. However, at high frequencies, the lid contributes the most to the piano sound.
-
time domain simulation of a piano part 1 model description
Mathematical Modelling and Numerical Analysis, 2014Co-Authors: Juliette Chabassier, Antoine Chaigne, Patrick JolyAbstract:The purpose of this study is the time domain modeling of a piano. We aim at explaining the vibratory and acoustical behavior of the piano, by taking into account the main elements that contribute to sound production. The Soundboard is modeled as a bidimensional thick, orthotropic, heterogeneous, frequency dependent damped plate, using Reissner Mindlin equations. The vibroacoustics equations allow the Soundboard to radiate into the surrounding air, in which we wish to compute the complete acoustical field around the perfectly rigid rim. The Soundboard is also coupled to the strings at the bridge, where they form a slight angle from the horizontal plane. Each string is modeled by a one dimensional damped system of equations, taking into account not only the transversal waves excited by the hammer, but also the stiffness thanks to shear waves, as well as the longitudinal waves arising from geometric nonlinearities. The hammer is given an initial velocity that projects it towards a choir of strings, before being repelled. The interacting force is a nonlinear function of the hammer compression. The final piano model is a coupled system of partial differential equations, each of them exhibiting specific difficulties (nonlinear nature of the string system of equations, frequency dependent damping of the Soundboard, great number of unknowns required for the acoustic propagation), in addition to couplings' inherent difficulties.
-
Modeling and simulation of a grand piano
Journal of the Acoustical Society of America, 2013Co-Authors: Juliette Chabassier, Patrick Joly, Antoine ChaigneAbstract:A time-domain global modeling of a grand piano is presented. The string model includes internal losses, stiffness and geometrical nonlinea- rity. The hammer-string interaction is governed by a nonlinear dissi- pative compression force. The Soundboard is modeled as a dissipative bidimensional orthotropic Reissner-Mindlin plate where the presence of ribs and bridges is treated as local heterogeneities. The coupling between strings and Soundboard at the bridge allows the transmission of both transverse and longitudinal waves to the Soundboard. The Soundboard is coupled to the acoustic field, whereas all other parts of the structure are supposed to be perfectly rigid. The acoustic field is bounded artificially using perfectly matched layers (PML). The discrete form of the equations is based on original energy preserving schemes. Artificial decoupling is achieved, through the use of Schur complements and Lagrange multipliers, so that each variable of the problem can be updated separately at each time step. The capability of the model is highlighted by series of simulations in the low, medium and high regis- ter, and through comparisons with waveforms recorded on a Steinway D piano. Its ability to account for phantom partials and precursors, consecutive to string nonlinearity and inharmonicity, is particularly emphasized.
-
Modeling the grand piano
2013Co-Authors: Antoine Chaigne, Juliette Chabassier, Patrick JolyAbstract:A global model of a piano is presented. Its aim is to reproduce the main vibratory and acoustic phenomena involved in the generation of a piano sound from the initial blow of the hammer against the strings to the radiation from Soundboard to the air. One first originality of the work is due to the string model which takes both geometrical nonlinear effects and stiffness into account. Other significant improvements are due to the combined modeling of the three main couplings between the constitutive parts of the instrument: hammer-string, string-Soundboard and Soundboard-air coupling.
-
Dynamical properties of piano Soundboards
Journal of the Acoustical Society of America, 2013Co-Authors: Antoine Chaigne, Benjamin Cotté, Roberto ViggianoAbstract:In pianos, the transfer of energy from strings to Soundboard and the radiation of sound are highly dependent on the dynamical properties of the Soundboard. In this paper, a numerical study is conducted for various rib configurations, showing that even slight irregularities in rib spacing can induce a strong localization of the Soundboard velocity pattern. The effective vibrating area can be further reduced due to the spatial filtering effect of the bridge. Numerical predictions of modal shapes and operating deflection shapes are confirmed by series of measurements made on upright piano Soundboards. Simulations of radiated pressure based on measured and calculated Soundboard velocity fields show that localization tends to broaden the cone of directivity and to reduce the number of lobes.
Xavier Boutillon - One of the best experts on this subject based on the ideXlab platform.
-
MAESSTRO: A sound synthesis framework for Computer-Aided Design of piano Soundboards
2019Co-Authors: Benjamin Elie, Juliette Chabassier, Xavier Boutillon, Kerem Ege, Benjamin Cotté, Bernard Laulagnet, Benjamin Trévisan, Nicolas ChauvatAbstract:The design of pianos is mainly based on empirical knowledge due to the lack of a simple tool that could predict sound changes induced by changes of the geometry and/or the mechanical properties of the Soundboard. We present the framework of a program for the Computer-Aided Design of piano Soundboards that is intended to bridge that gap by giving piano makers a tool to synthesize tones of virtual pianos. The sound synthesis is solely based on physical models of the instrument in playing situation. The calculation of the sound is split into several modules: computation of the modal basis of the stiffened Soundboard, computation of the string dynamics, simulation of the Soundboard dynamics excited by the string vibration, and calculation of the sound radiation. Reference tests of sound synthesis of real pianos as well as sound synthesis of modified pianos are used to assess our main objective, namely to reflect faithfully structural modifications in the produced sound, and thus to make this tool helpful for both piano makers and researchers of the musical acoustics community.
-
Spatial spectra of the eigenmodes of ribbed plates projected on dispersion branches
2017Co-Authors: Gautier Lefebvre, Xavier Boutillon, Marcel FilocheAbstract:A vast literature has been devoted to the transverse vibration and the sound radiation of ribbed plates over the last decades. The present study has been motivated by the analysis of the dynamical behaviour of piano Soundboards. As a rough approximation, a piano Soundboard can be considered as an orthotropic ribbed plate. Our purpose is to establish condensed descriptions for their dynamics. For low frequencies, regularly ribbed plates can be considered as homogeneous plates. It is usually considered that homogenization is valid only up to a frequency corresponding roughly to the confinement of one half wave-length between the (periodically spaced) ribs. Beyond that frequency, depending on the relative characteristic mobility of the ribs and that of the base plate, the ribs may constrain transverse waves to be guided between them. We focus here on the spatial spectrum of the normal modes of the ribbed plate (2D Fourier transforms of the modal shapes). It appears that most of the peaks of each spectrum can be seen as belonging to one of a few dispersion branches in an appropriate (w; k)-plane. Interestingly, different peaks of a spectrum (of one given mode) usually "belong" to different dispersion branches. When valid, this description may prove an interesting intermediate step to derive approximations for the sound radiation of such plates.
-
Localization in the piano Soundboard
2016Co-Authors: Gautier Lefebvre, Marcel Filoche, Xavier BoutillonAbstract:The Soundboard is the complex plane structure that radiates the piano sound. We focus on its structural vibrations. The arrangement of the stiffeners (parallel bars) displays some disorder (height, separation distance) that has been shown responsible for the localization of the vibrations above a precise frequency (Ege 2013, JSV; Chaigne 2013, JASA) By means of a finite-element method, we investigate the localization properties of the eigenmodes of a simplified Soundboard model. The localization occurs close to the band-edge of the first Brillouin zone, indicating the importance of a slightly disordered structure, similarly to photonic or phononic crystals with defects (John 1987, PRL). For structural parameters typical of a piano Soundboard, this phenomenon seems to force the Soundboard to remain in the subsonic regime in a very large frequency range. Moreover, by the adaptation of the theory of the localization landscape (Filoche 2012 PNAS), we compute a dual landscape (Lyra 2015 EPL) for the high-frequency modes of a stiffened orthotropic thin plate. This enables to predict the position of localized eigenmodes. [Work supported by the ANR grant ANR-14-CE07-0014.]
-
Localization in the piano Soundboard
The Journal of the Acoustical Society of America, 2016Co-Authors: G. Lefebvre, Marcel Filoche, Xavier BoutillonAbstract:The Soundboard is the complex plane structure that radiates the piano sound. We focus on its structural vibrations. The arrangement of the stiffeners (parallel bars) displays some disorder (height, separation distance) that has been shown responsible for the localization of the vibrations above a precise frequency (Ege 2013, JSV; Chaigne 2013, JASA) By means of a finite-element method, we investigate the localization properties of the eigenmodes of a simplified Soundboard model. The localization occurs close to the band-edge of the first Brillouin zone, indicating the importance of a slightly disordered structure, similarly to photonic or phononic crystals with defects (John 1987, PRL). For structural parameters typical of a piano Soundboard, this phenomenon seems to force the Soundboard to remain in the subsonic regime in a very large frequency range. Moreover, by the adaptation of the theory of the localization landscape (Filoche 2012 PNAS), we compute a dual landscape (Lyra 2015 EPL) for the high-frequ...
-
Vibroacoustics of the piano Soundboard: (Non)linearity and modal properties in the low- and mid-frequency ranges
Journal of Sound and Vibration, 2013Co-Authors: Kerem Ege, Xavier Boutillon, Marc RébillatAbstract:The piano Soundboard transforms the string vibration into sound and therefore, its vibrations are of primary importance for the sound characteristics of the instrument. An original vibro-acoustical method is presented to isolate the Soundboard nonlinearity from that of the exciting device (here: a loudspeaker) and to measure it. The nonlinear part of the Soundboard response to an external excitation is quantitatively estimated for the first time, at ≈ -40 dB below the linear part at the ff nuance. Given this essentially linear response, a modal identification is performed up to 3 kHz by means of a novel high resolution modal analysis technique (Ege et al., High-resolution modal analysis, JSV, 325(4-5), 2009). Modal dampings (which, so far, were unknown for the piano in this frequency range) are determined in the midfrequency domain where FFT-based methods fail to evaluate them with an acceptable precision. They turn out to be close to those imposed by wood. A finite-element modelling of the Soundboard is also presented. The low-order modal shapes and the comparison between the corresponding experimental and numerical modal frequencies suggest that the boundary conditions can be considered as blocked, except at very low frequencies. The frequency-dependency of the modal density and the observation of modal shapes reveal two well-separated regimes. Below ≈ 1 kHz, the Soundboard vibrates more or less like a homogeneous plate. Above that limit, the structural waves are confined by ribs, as already noticed by several authors, and localised in restricted areas (one or a few inter-rib spaces), presumably due to a slightly irregular spacing of the ribs across the Soundboard.
Kerem Ege - One of the best experts on this subject based on the ideXlab platform.
-
MAESSTRO: A sound synthesis framework for Computer-Aided Design of piano Soundboards
2019Co-Authors: Benjamin Elie, Juliette Chabassier, Xavier Boutillon, Kerem Ege, Benjamin Cotté, Bernard Laulagnet, Benjamin Trévisan, Nicolas ChauvatAbstract:The design of pianos is mainly based on empirical knowledge due to the lack of a simple tool that could predict sound changes induced by changes of the geometry and/or the mechanical properties of the Soundboard. We present the framework of a program for the Computer-Aided Design of piano Soundboards that is intended to bridge that gap by giving piano makers a tool to synthesize tones of virtual pianos. The sound synthesis is solely based on physical models of the instrument in playing situation. The calculation of the sound is split into several modules: computation of the modal basis of the stiffened Soundboard, computation of the string dynamics, simulation of the Soundboard dynamics excited by the string vibration, and calculation of the sound radiation. Reference tests of sound synthesis of real pianos as well as sound synthesis of modified pianos are used to assess our main objective, namely to reflect faithfully structural modifications in the produced sound, and thus to make this tool helpful for both piano makers and researchers of the musical acoustics community.
-
Comparisons between measured and predicted vibroacoustics characteristics of an upright piano Soundboard
2015Co-Authors: Benjamin Trévisan, Kerem Ege, Pierre Margerit, Bernard LaulagnetAbstract:The piano Soundboard is an orthotropic plate made of spruce, ribbed by multiple stiffeners (the ribs) parallel to the grain direction of the main panel’s wood and two addition beams (the bridges) nearly in a perpendicular direction. This complex structure transforms the piano string vibration (coupled to the Soundboard at the bridge) into sound; its vibrations and radiations are therefore of primary importance for the sound characteristics of the instrument. Several vibroacoustics models have been developed these last decades using different methodologies: finite element / numerical modeling (Berthaut et al., Applied Acoustics, 2003 ; Chaigne et al., JASA, 2013 ; Chabassier et al., JASA, 2013) or reduced models using global descriptors (Boutillon and Ege, JSV, 2013). An analytical model recently developed at LVA (Trevisan et al., ISMA 2014 / NOVEM 2015) is particularly well-adapted for a parametrical study and appears as an alternative to time-consuming numerical methodologies. The model is based on a variational approach that takes into account plate and superstructures energies. The Soundboard vibration is decomposed on the corresponding orthotropic simply supported unribbed plate modes. The aim of this analytical tool is ultimately to help piano manufacturers to predict the influence of structural modifications of the Soundboard (number/dimensions of ribs/bridges…) on the sound of the instrument. In order to validate the methodology and hypotheses done in the analytical model, we present and compare in this communication measured/predicted vibroacoustics quantities obtained for a same structure and under same (supposed) conditions: a Pleyel P131 upright piano Soundboard fixed on its wooden rim. The quantities compared are modal basis in the low-frequency domain [0-400Hz] and point mobility along the bridge for a larger frequency band [0-5kHz]. Results on vibrations are very satisfying demonstrating the validity of the model. Experimental radiation results (Soundboard radiated power) will also be given and compared to predicted quantities.
-
Comparisons between measured and predicted vibroacoustics characteristics of an upright piano Soundboard
2015Co-Authors: Benjamin Trévisan, Kerem Ege, Pierre Margerit, Bernard LaulagnetAbstract:The piano Soundboard is an orthotropic plate made of spruce, ribbed by multiple stiffeners (the ribs) parallel to the grain direction of the main panel’s wood and two addition beams (the bridges) nearly in a perpendicular direction. This complex structure transforms the piano string vibration (coupled to the Soundboard at the bridge) into sound; its vibrations and radiations are therefore of primary importance for the sound characteristics of the instrument. Several vibroacoustics models have been developed these last decades using different methodologies: finite element / numerical modeling (Berthaut et al., Applied Acoustics, 2003 ; Chaigne et al., JASA, 2013 ; Chabassier et al., JASA, 2013) or reduced models using global descriptors (Boutillon and Ege, JSV, 2013). An analytical model recently developed at LVA (Trévisan et al., ISMA 2014 / NOVEM 2015) is particularly well-adapted for a parametrical study and appears as an alternative to time-consuming numerical methodologies. The model is based on a variational approach that takes into account plate and superstructures energies. The Soundboard vibration is decomposed on the corresponding orthotropic simply supported unribbed plate modes. The aim of this analytical tool is ultimately to help piano manufacturers to predict the influence of structural modifications of the Soundboard (number/dimensions of ribs/bridges…) on the sound of the instrument. In order to validate the methodology and hypotheses done in the analytical model, we present and compare in this communication measured/predicted vibroacoustics quantities obtained for a same structure and under same (supposed) conditions: a Pleyel P131 upright piano Soundboard fixed on its wooden rim. The quantities compared are modal basis in the low-frequency domain [0-400Hz] and point mobility along the bridge for a larger frequency band [0-5kHz]. Results on vibrations are very satisfying demonstrating the validity of the model. Experimental radiation results (Soundboard radiated power) will also be given and compared to predicted quantities.
-
Piano Soundboard vibro-acoustic modeling through decomposition on the basis of orthotropic simply supported unribbed plate modes
2015Co-Authors: Benjamin Trévisan, Kerem Ege, Bernard LaulagnetAbstract:The piano Soundboard is an orthotropic plate made of spruce, ribbed by multiple stiffeners, with a big additional beam, nearly in a perpendicular direction, the bridge. This complex structure has an essential role in the working of the instrument. Indeed, since strings’ sections are too small to radiate by themselves, their vibrations are transmitted to the Soundboard which radiates efficiently the sound. The vibro-acoustic models of such a structure are rare and mechanisms involved in piano acoustical radiation are not so easy to undertake. The aim of this study is to concentrate efforts on the modeling of the ”radiator”: the piano Soundboard. In the present paper, focus will be done on the way to calculate the plate Soundboard vibration, in the case of special orthotropy, where the ribs and the bridge are present. We develop here a quasi-analytical model of the piano Soundboard vibro-acoustical behavior which allows us for example to estimate the sensitivity of rib spacing, or of the bridge on the modal shapes and radiation’s indicators as radiated power, space average velocity and Soundboard radiation factor through parametric studies.
-
Prediction of orthotropic ribbed plates' vibro-acoustics mechanisms: application to the piano Soundboard
2014Co-Authors: Benjamin Trévisan, Kerem Ege, Bernard LaulagnetAbstract:Since the strings of a piano cannot radiate sound due to their small sections, the vibrations are transmitted through the bridges to the piano Soundboard to increase radiation. This complex structure is made of a main spruce panel ribbed by several beams (ribs) in a direction orthogonal to the grain, and by two curved beams (bridges) in a direction nearly parallel to the grain. To understand the influence of superstructures (ribs, bridges) on the vibro-acoustic behavior of the Soundboard, an analytical modeling is presented here based on a variational approach taken into account plate's and ribs' energies. The study is carried out on a simplify rectangular Soundboard with special orthotropy and a single straight bridge. Bending, torsion and offset of the ribs are taken into account. In order to calculate the eigenmodes of the ribbed orthotropic plate, the whole vibratory problem is decomposed on the basis of simply supported unribbed plate modes. Examples of modal shapes of the Soundboard and images of the plate's velocity field in response of a driving force applied to the bridge are given. The influence of the bridge and the localization phenomenon above roughly 1kHz will be discussed. This analytical methodology appears as an alternative for the finite element modeling and is particularly adapted for a parametrical study. The numerical tool developed can be used by piano manufacturers to predict the influence of the numbers/geometry of ribs and bridges on the sound of the instrument.